Two-way radio

two way radioRadio Operatortwo-way radios2-way radioradiotwo-wayRadio Officerradiostransceivertransceivers
A two-way radio is a radio that can both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content.wikipedia
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Radio

radio communicationradio communicationswireless
A two-way radio is a radio that can both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content.
In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking and satellite communication among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter.

Walkie-talkie

walkie talkiewalkie-talkiesradio
Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds.
A walkie-talkie (more formally known as a handheld transceiver, or HT) is a hand-held, portable, two-way radio transceiver.

Transmitter

radio transmittertransmittersradio transmitters
A two-way radio is a radio that can both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content.
Transmitters are necessary component parts of all electronic devices that communicate by radio, such as radio and television broadcasting stations, cell phones, walkie-talkies, wireless computer networks, Bluetooth enabled devices, garage door openers, two-way radios in aircraft, ships, spacecraft, radar sets and navigational beacons.

Mobile radio

land mobilemobileland-mobile radio systems
Two-way radios are available in stationary (base station), mobile, and hand-held portable models.
The distinction between radiotelephones and two-way radio is becoming blurred as the two technologies merge.

Push-to-talk

push to talkPush to Talk over CellularPTT
When the user wants to talk he presses a "push-to-talk" button, which turns off the receiver and turns on the transmitter; when he releases the button the receiver is activated again.
Push-to-talk (PTT), also known as press-to-transmit, is a method of having conversations or talking on half-duplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode.

Base station

base stationsWireless base stationradio base station
Two-way radios are available in stationary (base station), mobile, and hand-held portable models. This defines systems where equipment cannot communicate without some infrastructure such as a repeater, base station or Talk-Through Base.

NXDN

Most modern conventional digital radios and systems (i.e., NXDN and DMR) are capable of automatic "roaming" where the radio automatically switches channels on a dynamic basis. Examples of digital communication technologies are all modern cellphones plus TETRA considered to be the best standard in digital radio and being the baseline infrastructure for whole of country networks, including manufacturers such as DAMM, Rohill, Cassidian, Sepura and others, APCO Project 25, a standard for digital public safety radios, and finally other systems such as Motorola's MotoTRBO, HQT's DMR, Nextel's iDEN, Hytera's DMR, EMC's DMR, and NXDN implemented by Icom as IDAS and by Kenwood as NEXEDGE.
NXDN is an open standard for public land mobile radio systems, that is systems of two way radios (transceivers) for bidirectional person-to-person voice communication.

Radio receiver

receiverreceiversRadios
A two-way radio is a radio that can both transmit and receive a signal (a transceiver), unlike a broadcast receiver which only receives content.
The receiver market was divided into the above broadcast receivers and communications receivers, which were used for two-way radio communications such as shortwave radio.

Continuous Tone-Coded Squelch System

CTCSSCTCSS tonePL
A valid transmission may be a radio channel with any signal or a combination of a radio channel with a specific Continuous Tone-Coded Squelch System (CTCSS) (or selective calling) code.
In telecommunications, Continuous Tone-Coded Squelch System or CTCSS is one type of circuit that is used to reduce the annoyance of listening to other users on a shared two-way radio communications channel.

Amateur radio

ham radioamateur radio licenseamateur
The term "amateur" is used to specify "a duly authorised person interested in radioelectric practice with a purely personal aim and without pecuniary interest;" (either direct monetary or other similar reward) and to differentiate it from commercial broadcasting, public safety (such as police and fire), or professional two-way radio services (such as maritime, aviation, taxis, etc.).

Radio repeater

repeaterrepeatersrelay station
This defines systems where equipment cannot communicate without some infrastructure such as a repeater, base station or Talk-Through Base.
A radio repeater is a combination of a radio receiver and a radio transmitter that receives a signal and retransmits it, so that two-way radio signals can cover longer distances.

APCO-16

APCO Project 16
Part of APCO Project 16 set standards for channel access times and delays caused by system overhead.
With the Federal Communications Commission's pending release of the first 800 MHz band licenses, the LEAA funded a project to develop required capabilities and standards needed in trunked public safety two-way radio systems.

Squelch

DCSDigital-Coded SquelchDigital Private Line
1940s tube-type land mobile two-way radios often had one channel and were carrier squelch.
Squelch is widely used in two-way radios and radio scanners to suppress the sound of channel noise when the radio is not receiving a transmission.

Mobile phone

cell phonemobile phonesmobile
A cell phone is an example of a full-duplex two-way radio.

Citizens band radio

CB radioCBCitizens Band
The citizen's band radio service (""CB"") has 40 channels. In the United States, some examples of two-way services are: citizen's band radio, Digital Electronic Message Service (DEMS), Family Radio Service (FRS), General Mobile Radio Service (GMRS), Multi-Use Radio Service (MURS), Business Radio Service (BRS), and PMR446.
Citizens band radio (also known as CB radio), used in many countries, is a land mobile radio system, a system allowing short-distance person-to-person bidirectional voice communication between individuals, using two way radios operating on 40 channels near 27 MHz (11 m) in the high frequency (a.k.a. shortwave) band.

Project 25

P25APCO Project 25APCO P25
Examples of digital communication technologies are all modern cellphones plus TETRA considered to be the best standard in digital radio and being the baseline infrastructure for whole of country networks, including manufacturers such as DAMM, Rohill, Cassidian, Sepura and others, APCO Project 25, a standard for digital public safety radios, and finally other systems such as Motorola's MotoTRBO, HQT's DMR, Nextel's iDEN, Hytera's DMR, EMC's DMR, and NXDN implemented by Icom as IDAS and by Kenwood as NEXEDGE.
P25 is a collaborative project to ensure that two-way radios are interoperable.

Multi-Use Radio Service

MURSMultiple Use Radio SystemMURS allocation
For example, in the United States, there is a block of 5 channels (pre-selected radio frequencies) are allocated to the Multiple Use Radio System. In the United States, some examples of two-way services are: citizen's band radio, Digital Electronic Message Service (DEMS), Family Radio Service (FRS), General Mobile Radio Service (GMRS), Multi-Use Radio Service (MURS), Business Radio Service (BRS), and PMR446.
In the United States, the Multi-Use Radio Service (MURS) is a licensed by rule two-way radio service similar to Citizens Band (CB).

Very high frequency

VHFVHF radioVHF band
The most common two-way radio systems operate in the VHF and UHF parts of the radio spectrum.
Common uses for radio waves in the VHF band are digital audio broadcasting (DAB) and FM radio broadcasting, television broadcasting, two way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with radio modems, amateur radio, and marine communications.

Digital Electronic Message Service

In the United States, some examples of two-way services are: citizen's band radio, Digital Electronic Message Service (DEMS), Family Radio Service (FRS), General Mobile Radio Service (GMRS), Multi-Use Radio Service (MURS), Business Radio Service (BRS), and PMR446.
The Digital Electronic Message Service (DEMS) is a two-way wireless radio service

Selective calling

Quik Call ITwo-tone sequentialtwo-tone sequential paging
A valid transmission may be a radio channel with any signal or a combination of a radio channel with a specific Continuous Tone-Coded Squelch System (CTCSS) (or selective calling) code.
Selective calling is used to address a subset of all two-way radios on a single radio frequency channel.

Professional mobile radio

PMRprivate mobile radioemergency-network
Professional mobile radio (also known as private mobile radio (PMR) in the UK and land mobile radio (LMR) in North America) are person-to-person two-way radio voice communications systems which use portable, mobile, base station, and dispatch console radios.

GE Marc V

GE Mark V
GE Marc V is a historic U.S. format or protocol of trunked, two-way radio introduced by General Electric Mobile Radio in the early 1980s.

Current loop

4-20 mA4-20mA4–20 mA
This type of radio system serves a purpose equivalent to a four-to-twenty milliampere loop.
Some devices, such as two-way radio remote control consoles, can reverse the polarity of currents and can multiplex audio onto a DC current.

Business band

Business Radio ServiceBlue Dot
In the United States, some examples of two-way services are: citizen's band radio, Digital Electronic Message Service (DEMS), Family Radio Service (FRS), General Mobile Radio Service (GMRS), Multi-Use Radio Service (MURS), Business Radio Service (BRS), and PMR446.
The pool describes a series of frequencies on the VHF and UHF two-way radio bands.

Ultra high frequency

UHFUHF bandultra-high frequency
The most common two-way radio systems operate in the VHF and UHF parts of the radio spectrum.
UHF wavelengths are short enough that efficient transmitting antennas are small enough to mount on handheld and mobile devices, so these frequencies are used for two way land mobile radio systems, such as walkie-talkies, two way radios in vehicles, and for portable wireless devices; cordless phones and cell phones.